Implantable medical devices with header structures including conductive paths that facilitate the interconnection of feedthrough conductors to electrical connectors

ABSTRACT

Implantable medical devices include header structures with conductive paths from the feedthrough conductors that may be located on one side of the device to electrical connectors that may be located on an opposite side of the device. The conductive paths may include conductive interconnect pins and lead frame conductors. The conductive interconnect pins may be located in holes present in a header body where the conductive interconnect pins are attached to the feedthrough conductors on one end and are attached to the lead frame conductors on the opposite end. The lead frame conductors then extend to the corresponding electrical connectors. The header body may provide cavities on each side to allow for the insertion of stack assemblies that include the electrical connectors and lead frame conductors.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.14/983,519, filed Dec. 29, 2015, entitled IMPLANTABLE MEDICAL DEVICESWITH HEADER STRUCTURES INCLUDING CONDUCTIVE PATHS THAT FACILITATE THEINTERCONNECTION OF FEEDTHROUGH CONDUCTORS TO ELECTRICAL CONNECTORS, nowU.S. Pat. No. 9,907,965, which claims the benefit of the filing date ofprovisional U.S. Patent Application No. 62/098,251 filed Dec. 30, 2014.

TECHNICAL FIELD

Embodiments relate to implantable medical devices that include headerstructures that receive feedthrough conductors and contain electricalconnectors. More particularly, embodiments relate to header structuresthat include conductive pathways that establish an interconnectionbetween the feedthrough conductors and the electrical connectors.

BACKGROUND

Implantable medical devices provide a medical function such aselectrical stimulation and/or physiological sensing. To provide themedical function, the implantable medical device includes electricalcircuitry contained within a housing. In many implantable medical devicedesigns, feedthrough conductors exit the housing and pass into a headerstructure mounted to the housing. The header structure includes one ormore bores where electrical connectors are present and electricalsignals are routed between the feedthrough conductors and the electricalconnectors.

Medical leads or lead extensions have proximal ends that are positionedwithin corresponding bores of the header structure. The medical leads orlead extensions include proximal contacts that make electricalconnection with the electrical connectors of the header structure.Conductors within an insulative lead body of the medical lead routeselectrical signals between the electrical contacts and electrodes at thedistal end of the lead body. The electrodes are positioned at a targetsite within the body by routing the lead between the implantation siteof the implantable medical device and the target site. Electricalsignals may then be passed between the electrical circuitry within thehousing of the implantable medical device and the electrodes at thetarget site.

Typically, a set of pre-shaped lead frame conductors establish aninterconnection of the feedthrough conductors to the electricalconnectors. In some cases, individual conductors are manually routedfrom the feedthrough to the electrical connector by bending theconductor as may be necessary to achieve the proper route duringconstruction of the header structure. In either case, problems may ariseduring manufacturing of the header structure, especially where thefeedthrough conductors enter the header structure on one side while theelectrical connectors are present on the opposite side, such as for aheader structure that has laterally spaced bores. The relatively smallsize of the header structure and the components within the headerstructure makes successfully routing individual conductor wires withoutcreating short circuits between adjacent conductors very difficult.Likewise, routing a lead frame conductor from one side of the headerstructure to another is troublesome as the lead frame has a pre-shapedconfiguration with bends that makes the manual routing awkward if notimpossible.

SUMMARY

Embodiments address issues such as these and others by providingimplantable medical devices with header structures that includeconductive paths that facilitate the interconnection of the feedthroughconductors to the electrical conductors. For instance, the conductivepath may be constructed of conductive pins that are attached to thefeedthrough conductors on one end and inserted into holes that pass fromone side of the header structure to the other, where lead frameconductors may then attach to the opposite end. Additionally, the leadframe conductors may interconnect the conductive pins to the electricalconductors by merely traveling in a relatively direct path, for instancein a vertical path relative to a horizontal lead bore, from the end ofthe conductive pin to the electrical connector on the same side of theheader structure. Also, the header structure may utilize a header bodythat has an open cavity for each bore, where the lead frame conductorson the side opposite the feedthrough conductors may be positioned bybeing introduced into the open cavity on that side of the header body.The conductive pins may have features to ease installation, such as ashoulder that engages a corresponding shoulder within the hole of theheader body.

Embodiments provide an implantable medical device that includes ahousing and circuitry within the housing, the circuitry providing aplurality of feedthrough conductors that exit the housing. Theimplantable medical device further includes a header structure having aplurality of holes passing from a first side of the header structure toa second side of the header structure and a plurality of conductivepins, with a conductive pin on the plurality present within acorresponding hole of the plurality of holes. The conductive pin has afirst end present on the first side of the header structure and a secondend present on a second side of the header structure, the second endbeing electrically coupled to a corresponding feedthrough conductor. Theimplantable medical device further includes electrical connectorspresent within an interior of the header structure and a first set oflead frame conductors with each lead frame conductor of the first setbeing electrically coupled to the first end of a correspondingconductive pin present within one of the holes and being electricallycoupled to a corresponding electrical connector within the headerstructure.

Embodiments provide a method of constructing an implantable medicaldevice that involves providing a header body having a first cavityexposed on a first side of the header body, having a second cavityexposed on a second side of the header body, and having at least onehole extending from the first side to the second side, the first cavitybeing laterally spaced from the second cavity. The method furtherinvolves providing a first stack assembly within the first cavity, thefirst stack assembly comprising at least one electrical connector and alead frame conductor electrically connected to the at least oneelectrical connector and providing a housing that houses electricalcircuitry, the electrical circuitry providing feedthrough conductorsthat exit from the housing. The method additionally involves inserting aconductive pin into the hole and establishing an electrical connectionbetween the lead frame conductor of the first side and a first end ofthe conductive pin present on the first side. The method also involvesmounting the header body to the housing and establishing an electricalconnection of a first feedthrough conductor to a second end of theconductive pin present on the second side.

Embodiments provide an implantable medical device that includes ahousing, circuitry within the housing, the circuitry providing aplurality of feedthrough conductors that exit the housing, and a headerstructure having a plurality of holes passing from a first side of theheader structure to a second side of the header structure. Theimplantable medical device further includes a plurality of conductivepaths, with a conductive path of the plurality passing through acorresponding hole of the plurality of holes, the conductive path havinga first end present on the first side of the header structure and asecond end present on a second side of the header structure, the secondend being electrically coupled to a corresponding feedthrough conductor.The implantable medical device also includes electrical connectorspresent within an interior of the header structure, wherein the headerstructure comprises a header body with a first cavity exposed to thefirst side of the header structure and a second cavity exposed to thesecond side of the header structure, with a first set of the electricalconnectors being present within the first cavity and with a second setof the electrical connectors being present within the second cavity. Thefirst end of each conductive path is electrically coupled to acorresponding electrical connector within the header structure.

Embodiments provide an implantable medical device that includes ahousing, circuitry within the housing, the circuitry providing aplurality of feedthrough conductors that exit the housing, and a headerstructure having a plurality of holes passing from a first side of theheader structure to a second side of the header structure. Theimplantable medical device further includes a plurality of conductivepaths, with a conductive path of the plurality passing through acorresponding hole of the plurality of holes, the conductive path havinga first end present on the first side of the header structure and asecond end present on a second side of the header structure with thesecond end being electrically coupled to a corresponding feedthroughconductor. Each hole of the plurality of holes of the header structuredefines a shoulder, wherein each of the conductive paths includes aportion that defines a shoulder, and wherein the shoulder of eachconductive path engages the shoulder of a corresponding hole of theplurality of holes. Electrical connectors are present within an interiorof the header structure and electrically coupled to correspondingconductive paths.

Embodiments provide an implantable medical device that includes ahousing, circuitry within the housing, the circuitry providing aplurality of feedthrough conductors that exit the housing, and a headerstructure having a plurality of holes passing from a first side of theheader structure to a second side of the header structure. Theimplantable medical device further includes a plurality of conductivepaths, with a conductive path of the plurality passing through acorresponding hole of the plurality of holes, the conductive path havinga first end present on the first side of the header structure and asecond end present on a second side of the header structure, the secondend being electrically coupled to a corresponding feedthrough conductor.A portion of each conductive path travels in a vertical direction fromthe corresponding hole to the corresponding electrical connector, witheach hole being aligned along a horizontal direction with acorresponding electrical connector. Electrical connectors are presentwithin an interior of the header structure and electrically coupled tocorresponding conductive paths.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an operating environment for various embodiments of theimplantable medical device.

FIG. 2 shows a left side view of an example of an implantable medicaldevice with a medical adhesive filler shown transparently for clarity ofillustration.

FIG. 3 shows a right side view of an example of a header structure of animplantable medical device with a medical adhesive filler showntransparently for clarity of illustration.

FIG. 4 shows a front left perspective view of the example of the headerstructure.

FIG. 5 shows a bottom perspective view of the example of the headerstructure.

FIG. 6 shows a left side view of the example of a header body of theheader structure.

FIG. 7 shows a right side view of the example of a header body of theheader structure.

FIG. 8 shows a front perspective view of the example of the header body.

FIG. 9 shows a front left perspective view of stack assemblies of theheader structure.

FIG. 10 shows a front right perspective view of stack assemblies of theheader structure.

FIG. 11 shows a front left perspective view of a second example of animplantable medical device with a medical adhesive filler showntransparently for clarity of illustration.

FIG. 12 shows a cross-sectional view taken through a header structure ofthe second example of the implantable medical device.

FIG. 13 shows a front right perspective view of the second example of animplantable medical device with a medical adhesive filler showntransparently for clarity of illustration.

FIG. 14 shows an example of an operational flow for constructing anexample of an implantable medical device according to the variousembodiments.

DETAILED DESCRIPTION

Embodiments provide conductive pathways that facilitate theinterconnection of feedthroughs to electrical connectors within a headerstructure of an implantable medical device. The embodiments providevarious features such as conductive pins that are inserted into holesthat pass from one side of the header structure where feedthroughconductors are located to another side of the header structure whereelectrical connectors are located. The conductive pins and holes of theheader structure may provide features to aid installation of theconductive pins such as a shoulder on the pin that engages a shoulderwithin the hole. The embodiments provide features such as a header bodyof the header structure where the header body has a cavity exposed tothe corresponding side of the header body which allows stack assembliesthat include electrical connectors, seals, set screw blocks, and thelike to be positioned within the cavity. Embodiments also providefeatures such as lead frame conductors that extend vertically, relativeto a horizontal bore defined by the electrical connectors within thecavity of the header body, from the conductor pin to the electricalconnector, where the hole that contains the conductor pin is aligned inthe horizontal direction relative to the corresponding electricalconnector.

FIG. 1 shows an example of an implantable medical system 100 thatincludes an implantable medical device 102 and associated medical leads104, which may also be a lead extension between the lead 104 and device102 for situations where the lead 104 is not long enough to span theentire distance, that are implanted in a patient 108. In this example,the implantable medical system 100 is situated within the patient 108 toprovide deep brain stimulation and/or sensing by having the medicalleads 104 extend into the brain where distal electrodes 106 arepositioned at a target site. However, it will be appreciated thataspects of the various medical device embodiments disclosed herein maybe used for other purposes including other neurological purposes likespinal cord stimulation and also cardiac purposes.

FIG. 2 shows a side view of the implantable medical device example 102with medical adhesive that isolates otherwise exposed electricalcomponents shown transparently so that the otherwise exposed electricalcomponents may be clearly viewed. A header structure 204 includes aheader body 203 and various internal components mounted within cavitiesof the header body 203. The cavities of the header body 203 are filledwith the medical adhesive that is transparent in FIG. 2 as well assubsequent figures herein. The implantable medical device 102 includes aportion 202 that includes the stimulation and sensing engine,controller, battery, telemetry circuits, and other components thatestablish the circuitry for performing the medical and communicationfunctions. The portion 202 includes a housing 201 that provides a sealedenclosure for the circuitry contained within the housing. Feedthroughconductors 220 that are connected to the various circuitry within thehousing 201 exit the housing 201 in a recessed area 226 that forms awindow to the feedthrough conductors 220.

The header structure 204 is mounted atop the portion 202, andspecifically atop the housing 201. The feedthrough conductors 220 areelectrically coupled to conductive pathways within the header structure204 that provide an electrical interconnection between each feedthroughconductor 220 and a corresponding electrical connector, such as a BalSeal® connector, of a stack assembly present within a dedicated andappropriately shaped cavity 218 in the interior of the header structure204. The cavity 218 is exposed on this side of the header body 203 priorto application of the medical adhesive that covers the cavity 218 andall components therein.

In this example, this side of the medical device 102 includes twovertically spaced stack assemblies 206, 208 within the cavity 218 thatshare a face 205. The face 205 provides entryways to the lead boresdefined by the stack assemblies 206, 208. The electrical connector maybe present on this second, or left, side of the medical device 102 thatis shown in FIG. 2, such as the electrical connector 212 and a set screwblock 214 of stack that acts as an electrical connector in the upperstack assembly 206. Insulative seals 210 are present between eachelectrical connector of a given stack assembly 206, 208 and between theface 205 and the adjacent electrical connector. A set screw with grommet216 is present within each set screw block 214.

In this example, a lead frame conductor 222 is provided for eachelectrical connector, or set screw block acting as an electricalconnector, on this side of the medical device 202. The lead frameconductor 222 has one end that acts as a pad for receiving the end ofthe feedthrough conductor 220, which may be welded or otherwise bondedin an electrically conductive manner to the pad of the lead frameconductor 222.

In this example, the feedthrough conductors 220 that are not associatedwith an electrical conductor of the side of the medical device 102 thatis shown in FIG. 2 are instead associated with an electrical connectoron a first, or right, side of the medical device 102. Therefore, thereis a challenge to establish an electrically conductive pathway from thefeedthrough conductor 220 on this side of the medical device 102 to theopposite side of the medical device 102. In this example, there areconductive interconnect pins that pass through corresponding holes fromthis side shown in FIG. 2, to the other side of the header structure 204as shown in FIG. 3. The conductive pins are discussed in more detailbelow with reference to FIGS. 9 and 10. In this example, the end of theconductive interconnect pins includes a tab 224 that is seen in FIG. 2that extends downward where the end of the feedthrough conductors 220are attached in an electrically conductive manner to the correspondingtab such as by a weld or other bond.

With reference to FIG. 3, there is an electrically conductive attachment240 of the conductive pin on this first side of the header structure 204to a corresponding lead frame conductor 238. The lead frame conductorextends vertically, relative to a horizontal lead bore, to acorresponding electrical connector, such as the electrical connector 232or a set screw block 236 acting as an electrical connector, to which thelead frame conductor 238 is attached. The electrical conductor 232 andset screw block 236 are part of a stack assembly present within adedicated and appropriately shaped cavity 228 of the header body 203.The cavity 228 is exposed on this side of the header body 203 prior toapplication of the medical adhesive that covers the cavity 228 and allcomponents therein.

In this example, this side of the medical device 102 includes twovertically spaced stack assemblies within the cavity 228 that share aface 207. The face 207 provides entryways to the lead bores defined bythe stack assemblies. Insulative seals 230 are present between eachelectrical connector of a given stack assembly and between the face 207and the adjacent electrical connector 232. A set screw with grommet 234is present within each set screw block 236.

FIG. 4 provides a perspective view that illustrates the entryways 242,244, 246, and 248 within the faces 205 and 207 for the four lead boresof this example. It will be appreciated that any number of lead boresmay be provided and that four are shown for purposes of example. It willalso be appreciated that any number of electrical connectors per leadbore may be provided and that a single electrical connector with asingle set screw block acting as an electrical connector are shown forpurposes of example.

FIG. 5 shows a perspective view that illustrates the bottom of theheader structure 204. In particular, tabs 250 can be seen in this view.These tabs 250 are used to attach the header structure 204 to thehousing 201 where the housing 201 includes receptacles that receive thetabs 250 to form an interference fit. The separation of the feedthroughconductor window 226 from the cavity 218 can also be seen. As discussedbelow with reference to FIG. 14, this separation of the feedthroughconductor window 226 from the cavity 218 allows the medical adhesivethat fills the cavity 218 and the window 226 to isolate the electricalcomponents and pathways from the external environment to be applied inseparate stages.

FIGS. 6-8 show views of the header body 203 prior to the installation ofany of the electrical components and conductive pathways. With referenceto FIG. 6, the header body 203 of this example provides grooves 256 forpositioning and isolation of the conductive pin tabs 224 and providesgrooves 258 for positioning and isolation of the lead frame conductors222. FIG. 8 shows the lateral spacing between the cavities 218, 228.

With further reference to FIGS. 6-8, the header body 203 also providesfeatures within the cavity 218 and within the cavity 228 that define thebores 252, 254, 262, and 264 to properly position the electricalconnectors, insulative seals, and set screw blocks. Additionally, theheader body 203 provides holes 260 that pass from one side to the otherside which properly positions and isolates the conductive interconnectpins. In this example, it can be seen from the hole 260 of FIG. 7 andthe location of the electrical connectors in FIG. 3 relative to theattachment point 240 which is within the hole 260 of FIG. 7, that eachhole 260 is aligned along a horizontal direction with a correspondingelectrical connector. This allows the lead frame conductor to travel asimple vertical direction to interconnect the conductive pin within thehole 260 to the electrical connector.

FIGS. 9 and 10 show perspective views of the electrically conductivepathways of the header structure that are established from thefeedthrough conductors 220 to the electrical connectors of the stackassemblies. In this example, each side has the two vertically spacedlead bore stack assemblies that are joined by the shared face 205 or 207to form the two stack duel bore assemblies 266 and 268. The conductivepathway to the first side, which is shown in FIG. 10, from the secondside where the feedthrough conductors of the device are exposed, whichis shown in FIG. 9, includes the vertical tab 224 which is perpendicularto the remainder of the horizontal conductive pin 225. This conductivepath further includes the lead frame conductor 238 which extends fromthe conductive pin 225 to the corresponding lead frame conductor 238.The horizontal conductive pin 225 is positioned within the correspondinghole 260 of the header body 203 as discussed above with reference toFIG. 6. By having the conductive pins 225 placed within the holes,during construction the lead frame conductors 238 are easily then placedinto the cavity 228 as discussed above to complete the conductive pathwithout tedious and problematic manual routing of the conductors fromone side of the device to the other and on to the correspondingelectrical connector.

Each of the components of the implantable medical device 102 shown inFIGS. 2-10 may be constructed of a variety of materials. For instancethe housing 201 may be constructed of biocompatible materials likeTitanium. The header body 203 may be constructed of biocompatiblematerials like Polysulfone. The faces 205, 207 may be constructed ofbiocompatible materials like Liquid Silicone Rubber. The set screwblocks 214, 236 may be constructed of biocompatible materials likeTitanium. The grommets 214, 234 may be constructed of biocompatiblematerials like Polysulfone. The insulative seals may also be constructedof biocompatible materials like Polysulfone. As discussed above, theelectrical connectors may be of various types including Bal Seal®connectors and may be constructed of materials like MP35N® alloys.

FIGS. 11-13 show views of an alternative example of an implantablemedical device 302. The implantable medical device example 302 includesa lower portion 402 that includes a housing 401 that houses theelectrical circuitry. A header structure 404 is mounted to the housing401. The header structure 404 includes a header body 403 that includes acavity 418 on the second, or left, side and a cavity 428 on the first,or right, side. As with the prior example, the cavities 418, 428 holdstack assemblies that include electrical connectors 412, insulativeseals 410, set screw blocks 414, 436, and associated set screw grommets416, and 434. Faces 405 and 407 define the entryways 442, 444, 446, and448 to the four lead bores of this example. Lead frame conductors 422and 438 complete the conductive pathway to the electrical connectors.Tabs 450 provide an interference fit to receptacles of the housing 401and header body 403 to lock the two together. The various components ofthis alternative example may be constructed of the same types ofmaterials of the like components of the prior example.

In this example, it should be noted that the conductive interconnectpins 424 do not have the vertical tabs of the prior example. However, inthis example, the feedthrough conductors 420 which are present within afeedthrough conductor window 426 are trimmed to different lengthsdepending upon whether a given feedthrough conductor 420 contacts a leadframe conductor 422 or a conductive interconnect pin 424. As shown forthe prior example in FIG. 2, those feedthrough conductors 220 aretrimmed to the same length.

Another aspect of the example of FIGS. 11-13 that differs from the priorexample is best shown in FIG. 12, where a cross-sectional view of theheader structure 404 is shown. Here, it can be seen that the conductiveinterconnect pins 424 include a larger diameter portion 472 and asmaller diameter portion 474. The transition from large diameter tosmall diameter creates a shoulder 468. Likewise, the hole 425 that theconductive interconnect pin 424 is placed within includes acorresponding larger diameter portion and smaller diameter portion toform a shoulder 470. The shoulder 468 of the pin 424 engages theshoulder 470 of the hole 425 to properly position the pin 424 within thehole 425 which further simplifies the introduction of the conductor pins424 to the housing body 403 during manufacturing.

FIG. 14 shows an example of a process for constructing an implantablemedical device that utilizes the conductive pathway of the headerstructure from the feedthrough conductor to the electrical connector. Inthis particular example, the implantable medical device includes leftand right stack assemblies providing left and right lead bores. It willbe appreciated that the left and right stacks may each include multiplelead bores that are vertically spaced as described above for theexamples of FIGS. 2-10. Initially, the first and second stack assembliesare created at an operation 502. This involves placing the set screwblock, electrical connectors, and insulative seals of a given stackassembly on a stack pin that holds each of the components in properalignment. The lead frame conductors may then be attached via a weld orother bond to each electrical connector, as well as to each set screwblock acting as an electrical connector, at an operation 504.

To prepare the header body for introduction of the stack assemblies, theconductive interconnect pins may be placed within the holes of theheader body that pass from one side to the other at an operation 506.This operation 506 may alternatively be performed prior to either orboth of the operations 502, 504. Once the conductive interconnect pinsare positioned within the lateral holes of the header body, the first orright side stack assembly may then be placed within the first or rightside cavity of the header body at an operation 508. At this point, thelower end of the lead frame conductors of this first stack assembly arepositioned at the end of the conductive interconnect pins present withinthe holes of the header body. The lower end of the lead frame conductorsis then attached to the end of the conductive interconnect pin by weldor other bond at an operation 510.

The second or left side stack assembly may be placed within the secondor left side cavity of the header body at an operation 512. At thispoint, the header structure includes all of the internal components andthe process proceeds by inserting the grommets for the set screws andthen filling the cavities with medical adhesive to cover the stackassemblies within the cavities at an operation 514. The medical adhesiveis then allowed to cure, which then effectively isolates the stackassembly components from the external environment. The medical adhesivedoes not flow into the feedthrough window of the header structure suchthat the ends of the lead frames and the ends of the conductive pins atthe feedthrough window remain exposed. It will be appreciated that themedical adhesive over the stack assemblies may instead be added at alater stage of the process if the stack assemblies are temporarily heldin place within the cavities by another technique such as fixturing orretention features within the cavities.

At this point, the header structure that includes the header body andstack assemblies is attached to the housing of the lower portion of themedical device at an operation 516. At this stage, the housing of themedical device already contains the electrical components and thefeedthrough conductors are exposed at the top of the housing. Asdiscussed for the embodiments of FIGS. 2-13, tabs may be included toprovide an interference fit within receptacles at the bottom of theheader body and at the top of the housing to effectively lock the headerstructure to the housing.

Once the header structure is attached to the housing, the lower end ofthe lead frame conductors of this first stack assembly are positionednear the exposed end of the feedthrough conductors present at thefeedthrough conductor window of the header body. Likewise, theconductive interconnect pins are also positioned near the exposed end ofthe feedthrough conductors. However, the feedthrough conductors may belonger than necessary to reach the lead frame conductor ends and/or theend of the conductive interconnect pins that is exposed on this secondor left side of the header body. Therefore, the feedthrough conductorsmay be trimmed to size prior to further attachment. Then the lower endof the lead frame conductors which may have a pad shape as well as theexposed end of the conductive interconnect pins, such as the verticaltab 224 of FIG. 2 which may act as a pad, are then attached to the endof the corresponding feedthrough conductor by weld or other electricallyconductive bond at an operation 518.

Once the electrical coupling to the feedthrough conductors is complete,the feedthrough window where the attachment to the feedthroughconductors has occurred may then be filled with medical adhesive at anoperation 520. The medical adhesive is allowed to cure, and thiseffectively isolates the feedthrough conductors and the connections tothe feedthrough conductors from the external environment. Additionally,if the medical adhesive has not yet been applied over the stackassemblies, the medical adhesive may then be added over the stackassemblies at this stage as well.

Thus, as demonstrated by this process, there is no tedious conductorrouting necessary for providing a conductive path from the feedthroughside of the header structure to the electrical connectors of the leadbore on the opposite side. Conductive interconnect pins are easilyinserted into the holes while stack assemblies are easily inserted intothe cavities on each side of the device that are exposed to the exteriorprior to being filled with the medical adhesive.

While embodiments have been particularly shown and described, it will beunderstood by those skilled in the art that various other changes in theform and details may be made therein without departing from the spiritand scope of the invention.

What is claimed is:
 1. An implantable medical device, comprising: ahousing; circuitry within the housing, the circuitry comprising aplurality of feedthrough conductors that exit the housing; a headerstructure having a plurality of holes passing from a first side of theheader structure to a second side of the header structure; a pluralityof conductive paths, with a conductive path of the plurality passingthrough a corresponding hole of the plurality of holes, the conductivepath having a first end present on the first side of the headerstructure and a second end present on the second side of the headerstructure, the second end being electrically coupled to a correspondingfeedthrough conductor of the plurality of feedthrough conductors; aplurality of electrical connectors present within an interior of theheader structure, wherein the header structure comprises a header bodywith a first cavity exposed to the first side of the header structureand a second cavity exposed to the second side of the header structure,with a first set of the electrical connectors of the plurality ofelectrical connectors being present within the first cavity and with asecond set of the electrical connectors of the plurality of electricalconnectors being present within the second cavity, and wherein the firstend of each conductive path of the plurality of conductive paths iselectrically coupled to a corresponding electrical connector of theplurality of electrical connectors within the header structure.
 2. Theimplantable medical device of claim 1, wherein the conductive path ofthe plurality comprises: a conductive pin present within thecorresponding hole of the header structure with a first end and a secondend, the second end being electrically coupled to the correspondingfeedthrough conductor; and a lead frame conductor electrically coupledto the first end of the conductive pin and electrically coupled to thecorresponding electrical connector.
 3. An implantable medical device,comprising: a housing; circuitry within the housing, the circuitryproviding a plurality of feedthrough conductors that exit the housing; aheader structure having a plurality of holes passing from a first sideof the header structure to a second side of the header structure; aplurality of conductive paths, with a conductive path of the pluralityof conductive paths passing through a corresponding hole of theplurality of holes, the conductive path having a first end present onthe first side of the header structure and a second end present on asecond side of the header structure, the second end being electricallycoupled to a corresponding feedthrough conductor of the plurality offeedthrough conductors, wherein each hole of the plurality of holes ofthe header structure defines a first shoulder, wherein each of theconductive paths of the plurality of conductive paths includes a portionthat defines a second shoulder, and wherein the second shoulder of eachconductive path engages the first shoulder of a corresponding hole ofthe plurality of holes; a plurality of electrical connectors presentwithin an interior of the header structure and electrically coupled tocorresponding conductive paths of the plurality of conductive paths. 4.The implantable medical device of claim 3, wherein the conductive pathof the plurality comprises: a conductive pin present within thecorresponding hole of the header structure with a first end and a secondend, the second end being electrically coupled to the correspondingfeedthrough conductor, the conductive pin defining the second shoulderthat engages the first shoulder of the corresponding hole; and a leadframe conductor electrically coupled to the first end of the conductivepin and electrically coupled to a corresponding electrical connector ofthe plurality of electrical connectors.
 5. An implantable medicaldevice, comprising: a housing; circuitry within the housing, thecircuitry providing a plurality of feedthrough conductors that exit thehousing; a header structure having a plurality of holes passing from afirst side of the header structure to a second side of the headerstructure; a plurality of conductive paths, with a conductive path ofthe plurality of conductive paths passing through a corresponding holeof the plurality of holes, the conductive path having a first endpresent on the first side of the header structure and a second endpresent on a second side of the header structure, the second end beingelectrically coupled to a corresponding feedthrough conductor of theplurality of feedthrough conductors; a plurality of electricalconnectors present within an interior of the header structure andelectrically coupled to corresponding conductive paths of the pluralityof conductive paths, wherein a portion of the conductive path travels ina vertical direction from the corresponding hole to a correspondingelectrical connector of the plurality of electrical connectors, with thecorresponding hole being aligned along a horizontal direction with thecorresponding electrical connector.
 6. The implantable medical device ofclaim 5, wherein the conductive path of the plurality comprises: aconductive pin present within the corresponding hole of the headerstructure with a first end and a second end, the second end beingelectrically coupled to the corresponding feedthrough conductor; and alead frame conductor electrically coupled to the first end of theconductive pin and electrically coupled to the corresponding electricalconnector, wherein the lead frame conductor travels in the verticaldirection.